(Reuters) - Hawaii's attorney general issued a formal advisory opinion on Wednesday that said daily fantasy sports contests, such as those run by FanDuel and DraftKings, constitute illegal gambling under existing state laws.

"Gambling generally occurs under Hawaii law when a person stakes or risks something of value upon a game of chance or upon any future contingent event not under the person’s control," Hawaii Attorney General Doug Chin said in a statement. "The technology may have changed, but the vice has not."

Playing in a league with friends or colleagues, considered "social gambling," is legal in Hawaii, while daily fantasy sports contests involve hundreds or thousands of people, bets of up to $1,000 and top prizes of up to $1 million, the statement said.

The fast-growing, multibillion-dollar fantasy sports industry dominated by DraftKings and FanDuel has drawn increased attention from state regulators over the past year, with the attorneys general of New York, Illinois, Texas and Nevada challenging their legality.

The games are illegal in Arizona, Iowa, Louisiana, Montana and Washington. The attorneys general of New York and Illinois have also declared the games illegal, but those rulings are being challenged in state courts.

Nevada has said fantasy sports companies cannot operate in the state unless they receive gaming licenses.

(Reporting by Eric Beech and Eric Walsh in Washington; Editing by Diane Craft)